Long before the shooting of 18-year-old Michael Brown brought national attention to racial tensions in Ferguson, Missouri, zealous ticketing by a string of similar towns across the north side of St. Louis County had fed friction between the area’s largely white police departments and a growing black population.

An analysis by NBC News indicates that in recent years, Ferguson and other nearby jurisdictions have issued citations for low-level traffic and other violations at a per capita rate as much as a dozen times higher than cities in other parts of suburban St. Louis.

St. Louis County has 90 municipalities within its 524 square miles, and towns with populations as small as 800 people have their own police forces. Given the dense patchwork of towns and police departments, a single short car trip includes the possibility of multiple traffic stops. One seven-mile stretch of Interstate 70, for example, passes through eight different cities that can issue violations.

“If you’re driving to get to highway 70 to go to work, you drive through two to three municipalities, each of which can ticket you and make your life really difficult,” said Thomas Harvey, executive director of ArchCity Defenders, a law firm that represents low-income people in the area and recently released a report on local municipal courts.

Data from the State Attorney General’s Office also shows that per capita, black drivers in the county are 66 percent more likely to be stopped than whites, and more likely to be arrested once stopped. The result, in a section of the county where the poor black population is growing and the older white population is declining, is that much of the interaction between police and the newer residents takes place during traffic stops.

“It’s not just Ferguson, it’s this whole region,” said Harvey. “My clients say that the police officer and the judge and the prosecutor are not on their side, and they are just viewed as a source of revenue."

The contrast between the north county towns and other more affluent cities can be stark. Ferguson, a city of about 21,000, filed 11,400 traffic cases in fiscal year 2013. Chesterfield, a largely white city in the western suburbs, filed almost the exact same number -- but is more than twice Ferguson's size.

Cases involving non-traffic ordinances, which range from loitering and trespassing to petty larceny, provide an even starker contrast, with Ferguson filing almost a dozen times as many per capita. Ferguson in fiscal year 2013 filed more than 12,300 such cases, more than any other city in the county, and up from 8,800 in 2009. Chesterfield filed just 2,300 in 2013.

Ferguson is not alone in its approach. Before dissolving its police department last year, Cool Valley, a majority-black city of fewer than 1,200, filed 7,558 non-ordinance violation cases and 1,717 traffic cases that did not involve drugs or alcohol.

In Carleton Park, where blacks now account for about half of the 1,300 residents, the combined total of tickets for both types of offenses rose more than 50 percent between 2009 and 2013 to nearly 7,500. In contrast, officials in the affluent, white western suburb of Ballwin, which has 24 times the population, wrote about 9,000 tickets.

As cities in North County have gotten poorer and the effects of the recession linger, several have had to cut back on services to save costs. But many have seen their collections of fees and fines increase.

Budget documents show that Ferguson City officials expected to bring in about $2.6 million in fines and public safety revenues for the year ending in June 2013, an increase of more than 40 percent from 2010.

The nearby suburb of St. Ann, population 13,000, had lost tax revenue in 2011 when two major retailers moved away. That year police began to crack down on speeders along a stretch of Interstate 70 as part of a program to reduce accidents. It passed an ordinance that allowed the city to levy speeding tickets with fines twice that of state highway patrol. Revenue from the court has shot up nearly 170 percent to an estimated $3.1 million at the end of 2013.

Some officials have been critical of the rash of ticketing in northern St. Louis County. Among them is former St. Louis County Police Chief Tom Fitch. In a blog written before he retired last February, he railed in particular against speed cameras, which some towns have put up along major roadways to slow traffic, or, according to Fitch, “in order to generate as many violations as possible.” The result, he said, was to “feed off some of the poorest people in the St. Louis region.”

But St. Ann Police Chief Aaron Jimenez rejects that claim, saying the enforcement has reduced accidents significantly in recent years. “I’ve said since the beginning if you don’t break the law, then you don’t have anything to worry about,” he said.

"People don’t get the message unless it hurts the pocketbook, and we all know that.”

“Your naysayers are the ones who have gotten arrested for committing crimes, have received traffic violations," he added. "Half of the people who didn’t have attitudes would probably not have received those traffic tickets.”

Representatives of the city of Ferguson did not immediately respond to a request for comment.

Defenders cite a number of possible reasons for increased ticket writing other than a desire for revenue, like a rise in low level crimes or quality of life complaints. The cities along I-70 that recently implemented speed cameras and enforcement programs say these were meant to address high-speed accidents. In Ferguson, part of the impetus was a desire to improve the quality of life and attract investment. Ferguson ran an aggressive “nuisance abatement” campaign to lure development, according to budget documents.

But the perception among many caught up in the system is that the enforcement is about race and revenue, not public safety.

“It’s all about money -- that’s all they want,” said Antonio Morgan, 28, a resident of nearby Hazelwood who has been in and out of the county’s municipal courts since he was 16. “They don’t protect and serve anymore. When I was a kid, you talked to the police officers. In a black neighborhood, you can’t walk down the street without them pulling up on you. In the white community, they’re not doing that.”

From his perch as a part-time municipal judge in Overland, a city of 16,000 southwest of Ferguson, Frank Vatterott has watched the opportunity for people to be ticketed grow.

“There’s a lot more regulatory ordinances now that weren’t around before,” said Vatterott, a veteran of 34 years on the bench. “So there’s a lot more opportunity for police to stop people.”

Ordinances range from loitering and storing tires out of doors to assault and petty theft, and many have legitimately violated them. Those with means can generally pay the fine and walk away. But for those in poverty, said Vatterott, a small violation can become web of ticketing, debt, and if people don’t, or can’t, show up in court to pay it, warrants and arrest. Residents can end up with warrants in multiple cities, not to mention a license suspended for failure to pay, making getting to court even harder.

“It becomes a vicious cycle for defendants who are largely poor,” he said. He added that as a judge he has little choice but to issue a warrant when someone fails to show up.

Some cities have instituted amnesty days to help people clear outstanding warrants and begin to untangle themselves from the court. But with more than 40,500 outstanding warrants in Ferguson along as of 2013, many remain enmeshed.

No one claims that tickets in St. Louis County are behind the protests that have sparked national attention. But the longstanding perception that things are unfair in St. Louis County has mattered, said Morgan of Hazelwood.

“When the police treat you unjustly, and nobody hears you, and nobody stands up for you, you get frustrated,” said Morgan. “When an incident happens, now you’re ready to act out. Because you feel this is the only way anybody’s going to hear you.”